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Kumar E.R.,Sri Ramakrishna Mission Vidyalaya | Kamzin A.S.,RAS Ioffe Physical - Technical Institute
Journal of Magnetism and Magnetic Materials | Year: 2015

Mn substituted NiFe2O4 ferrite nanoparticles (Mn-NiFe2O4) were synthesized by the auto-combustion method. Their actions were carried out at different fuel ratios (50%, 75% and 100%). The nanoparticles have been investigated by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. The average crystallite size of the synthesized and annealed samples was between 25 and 75 nm, which were found to be dependent on both fuel ratio and annealing temperatures. However, lattice parameters, interplanar spacing and grain size were controlled by varying the fuel ratio. Magnetic characterizations of the nanoparticles were carried out using a vibrating sample magnetometer at room temperature. The saturation magnetization was computed and found to lie between 6 emu/g and 57 emu/g depending on the particle size of the studied sample. The coercivity was found to exhibit non-monotonic behavior with the particle size. Such behavior can be accounted for by the combination between surface anisotropy and thermal energies. The value of dielectric constant and dielectric loss was found to exhibit almost linear dependence on the particle size. © 2014 Elsevier B.V. All rights reserved.

Gnanamoorthi K.,Government of Tamilnadu | Balakrishnan M.,Government of Tamilnadu | Ranjith Kumar E.,Sri Ramakrishna Mission Vidyalaya
Materials Science in Semiconductor Processing | Year: 2015

Pure and Ce doped ZrO2 nanostructures have been synthesized by the microwave irradiation method. The prepared nanoparticles were characterized by various analytical techniques like Thermogravimetric and Differential Thermal Analysis (TG-DTA), X-Ray Diffraction (XRD), Fourier Transform Infra-Red Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive Spectrum (EDS) and Transmission Electron Microscopy (TEM). The XRD pattern of Ce doped ZrO2 nanoparticles have been confirms that the tetragonal structure. TEM observations indicated that the average particle size of the pure ZrO2 some particles spherical shaped and some particles agglomeration in the range of 16-44 nm. Whereas on addition of Ce agglomeration in the range of 32-56 nm. The pure ZrO2 and Ce doped ZrO2 nanoparticles were further characterized for their optical properties by UV-vis reflectance spectra (DRS) and Photoluminescence (PL) spectroscopy. © 2014 Elsevier Ltd. All rights reserved.

Sulthana A.,JSS University | Latha K.C.,JSS University | Rathan R.,JSS University | Sridhar R.,Sri Ramakrishna Mission Vidyalaya | Balasubramanian S.,JSS University
Water Science and Technology | Year: 2014

Wastewater treatment plant monitoring is an essential part of effective wastewater management. The analysis of eight physico-chemical parameters of untreated wastewater was carried out at Vidyaranyapuram sewage treatment plant, Mysore, India. Factor analysis (FA) was applied to the untreated wastewater data matrix, and pollution was found to be the most contributing factor, explaining 22.31% of the total variance (chloride, biochemical oxygen demand, chemical oxygen demand and total dissolved solids). The second most contributing factor was found to be nitrification which explained 21.11% of the total variance (pH and nitrate), whereas the salinization factor contributed 16.98% of the total variance (total solids and total suspended solids). FA regression scores could not satisfactorily classify the data matrix with respect to the seasonal variations. Discriminant analysis (DA) was used to find the seasonal variations in the data matrix, and the standard mode DA explained 66.6% of total variance by grouping the cases with respect to seasons. © IWA Publishing 2014.

Sulthana A.,JSS University | Latha K.C.,JSS University | Imran M.,Applied Information Sciences | Rathan R.,JSS University | And 2 more authors.
Water Science and Technology | Year: 2014

Fuzzy principal component regression (FPCR) is proposed to model the non-linear process of sewage treatment plant (STP) data matrix. The dimension reduction of voluminous data was done by principal component analysis (PCA). The PCA score values were partitioned by fuzzy-c-means (FCM) clustering, and a Takagi-Sugeno-Kang (TSK) fuzzy model was built based on the FCM functions. The FPCR approach was used to predict the reduction in chemical oxygen demand (COD) and biological oxygen demand (BOD) of treated wastewater of Vidyaranyapuram STP with respect to the relations modeled between fuzzy partitioned PCA scores and target output. The designed FPCR model showed the ability to capture the behavior of non-linear processes of STP. The predicted values of reduction in COD and BOD were analyzed by performing the linear regression analysis. The predicted values for COD and BOD reduction showed positive correlation with the observed data. © IWA Publishing 2014.

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